Process for the manufacture of optically brightened shaped products from regenerated cellulose



United States Patent O US. Cl. 106-165 6 Claims ABSTRACT OF THE DISCLOSURE A process for the production of optically brightened shaped articles from regenerated cellulose, which comprises submitting to precipitation and shaping a viscose composition to which has been previously added a solution of an optical brightener in an emulsifier.

The brightener should at most be only sparingly soluble in water to avoid a solution of the brightener in the coagulating bath. On the other hand, it must be possible to dissolve the brightener in the emulsifiers to be used, if necessary with the aid of a suitable solution promoter.

The emulsifiers used are nonionic substances, especially polyglycol condensation products with higher alcohols and with para-alkyl phenols containing higher alkyl radicals or reaction products of long chain fatty acids with substituted amines.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my application Ser. No. 485,110, filed Sept. 3, 1965, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a process for the manufacture of optically brightened shaped articles from regenerated cellulose treated with organic, water-insoluble brightening agents.

Shaped products, especially textile fibers, can be optically brightened during their manufacture by one of two fundamentally different methods: During the finishing of the material it may be treated in an after-treating bath, especially in the scrooping bath, with a water-soluble brightening agent which deposits on the material from these baths more or less rapidly, or the optical brightener may be incorporated with the mass from which the product is shaped.

Whereas there is as a rule no difliculty involved in brightening fibers from regenerated cellulose in an aftertreating bath, there is as yet no satisfactory working method available for incorporating brightening agents in the viscose rayon spinning mass. To-date there are two possibilities available: (1) incorporation of water-soluble optical brighteners with the viscose rayon spinning mass; (2) incorporation of finely dispersed water-insoluble brighteners with the viscose rayon spinning mass. Neither of these methods gives satisfactory results. When water-soluble optical brighteners are added to the viscose rayon spinning mass, a substantial share thereof passes into the coagulating bath and/or into the after-treating baths. The presence of optical brighteners may be particularly objectionable in scrooping baths since the latter are used for various products, including those which are not intended to be brightened. In addition, the brightener in the scrooping bath attains in the course of time a concentration that may cause patchy brightening effects. The second method referred to above, that is to say the incorporation of finely dispersed water-insoluble brighteners with the viscose rayon spinning mass, produces as a rule no brightening effects or only minor ones and, in addition, in many cases the brighteners own color causes yellowing of the material under treatment.

SUMMARY OF THE INVENTION The present invention provides a process in which the brightener is added to the viscose rayon mass as described for the second method referred to above, but it produces good brightening effects that are fast to washing. According to the present process for the manufacture of optically brightened shaped products from regenerated cellulose a solution of an optical brightener in an emulsifier is added to the viscose spinning mass before its coagulation and shaping.

The term regenerated cellulose as used in this context refers to material obtained from natural cellulose by alkalinization, sulfidation and shaping in a coagilating bath, with the viscose rayon obtained by sulfidation and dissolution being made up, for example, in tows, foils or tapes or preferably fibers. Either continuous or staple fibers may be produced.

The optical brighteners to be used in the present process may belong to a wide variety of chemical compounds. Inter alia, for example, there may be used dib nzoxazolylthiophenes, 4,4 di-triazinylaminostilbene-Z,2'-disulfonic acids further substituted on the triazine rings, coumarins or 1,4-distyrylbenzenes. The brightener should at most be only sparingly soluble in water so that the coagulating or scrooping bath will not dissolve an appreciable amount of the brightener concerned. Thus, for example, the above-mentioned 4,4 di-triazinylaminostilbene-2,2'-disulfonic acids should contain no further groups imparting solubility in water. On the other hand, it must be possible to dissolve the brightener in the emulsifiers to be used in the present process, if necessary with the aid of a suitable solution promoter. When brighteners are used that are free from solubilizing groups, there is practically no risk of their migration from the cellulose material into the coagulating bath or other treatment bath.

Apart from the brighteners the performance of the present process requires the use of emulsifiers, that is to say, quite generally speaking, surface-active substances. It is of advantage to use as such substances nonionic emulsifiers, especially polyglycol compounds containing a higher aliphatic hydrocarbon residue. A large variety of such products is known; they are obtained, for example, by an additive reaction of ethylene oxide with higher alcohols, with para-alkylphenols containing higher alkyl radicals or with higher alkylmercaptans.

Further suitable products are the reaction products of fatty acids of higher molecular weight with hydroxyalkylamines such as triethanolamine and more especially diethanolamine which may be reacted with ethylene oxide.

In many cases, especially when it is difficult to find an emulsifier in which the brightener concerned is sufficiently soluble, it is advantageous to use additionally an organic solvent which may be miscible with water in all proportions, as is the case e.g. with dioxane, or it may be only restrictedly water-miscible, for example to an extent up to percent, as is the case with butanol or cyclohexane. It is also of great advantage to add a higher fatty acid, such as oleic, stearic, palmitic or lauric acid, or a salt thereof.

For the manufacture of the brightener solutions there are substantially four possibilities available:

(a) The optical brightener is dissolved in an organic solvent which is readily miscible with water (preferably in all proportions), such as dioxane, glycol monobutyl ether or propanol, and the emulsifier is added;

(b) the optical brightener is dissolved in an organic solvent that is mostly only sparingly and Water-miscible, such as cyclohexanone or butanol, the emulsifier is added;

(0) the optical brightener is dissolved in the emulsifier alone;

(d) the optical brightener is dissolved in a water-miscible or water-miscible solvent, the emulsifier is added, and the organic solvent is distilled off.

It is also possible to use mixtures of solvents.

The amount of brightener to be used in the present process depends on its constitution and on the strength of the desired effect; in general, it is advantageously about 0.1%, though it is often possible to achieve a distinct effect with as little as 0.01%, whereas amounts in excess of 1% are practically excluded. (The percentages are referred to the Weight of the cellulose material to be brightened.

For the preparation of the solutions of the brightener a multiple, for example 20 to 500 times, of emulsifier and of organic solvent, if used, is as a rule required. At any rate it must be ensured that the brightener has dissolved completely before the solution is added to the viscose. The solution can be added in the desired amount directly to the viscose rayon spinning mass, or else a concentrated stock solution of the optical 'brightener in the emulsifier and, if desired, in the organic solvent may be prepared. Furthermore, it is possible to add the brightener solution to the alkalinized cellulose before proceeding to the sulfidation.

During the shaping of the viscose-which may be carried out in the usual manner, especially when the spinning mass issues from the spinnerets andenters the coagulating bath, or under certain conditions partially only during after-treatments in further baths-the brightener is precipitated again from its solution in a very finely dispersed form, but most of it remains in the solidified spinning mass, in fact the more of it the less soluble it is in water.

By this process good to excellent brightening elfects are achieved which is in contrast to the second method mentioned above in which the brightener is incorporated in solid form with the viscose. The brightening efiects obtained can be further improved by a chemical :bleach, for example with peroxide or hyperchlorite.

Parts and percentages in the following examples are by weight.

Example 1 One of the spinning solutions 1 to 9 described below is stirred into 987 parts of ripened viscose ready for spinning, having a content corresponding to 75 parts of cellulose, and further containing 0.75 part of titanium dioxide. The viscose is then spun in the usual manner with a coagulating bath containing sulfuric acid to form long fibers. The resulting fibrous material displays a strong brightening eifect of satisfactory to good fastness to light and very good fastness to water and washing.

If, in a comparative test, a water-insoluble brightener, not in the form of a solution but of an aqueous dispersion having an average particle sibe of 0.5a, is added to the viscose, all that is achieved as a rule is a certain yellowing and no brightening effect.

0.075 part of the brightener of the formula 0.075 part of the brightener of the formula 3 parts of oleic acid polyglycol ester from polyglycol of molecular weight 300 3 parts of polyethyleneglycol tertiary dodecyl thio ether 1.2 parts of oleic acid, pure 0.8 part of water 0.075 part of the brightener of the Fomula l 4.5 parts of cyclohexanone 4 parts of the adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol 4 parts of oleic acid, pure 0.075 part of the brightener of the formula (3) N HCCH N u u o-0 /o0 \O/ s \0/ 10 parts 'of dioxane 4 parts of the adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol 4 parts of oleic acid, pure I so H H s Q 7 parts of dioxane 10 parts of N-methylpynolidone 3 parts of oleic acid polyglycol ester from polyglycol of 4 parts of the adduct from 8 mols of ethylene oxide with molecular weight 300 1 mol of para-tertiary octylphenol 3 parts of polyethyleneglycol tertiary dodecyl thio ether 4 parts of oleic acid, pure 1.2 parts of oleic acid, pure Example 2 03 Part of water When instead of one of the solutions 1 to 10, 2 parts of the stock solution 11 or 5.6 parts of the stock solu- 0.075 part of the brightener of the formula tion 12 are added to the viscose, and the process is other- (5) wise carried out in an identical manner as in Example 1,

I N [Q good brightening effects are likewise achieved. i

N CNH I ,O

\ \0 0.5 part of the brightener of the Formula 2 L 5 parts of dioxane 5 parts of water 10 Parts of dioxane 3 parts of the adduct from 8 mols of ethylene oxide with 4 parts of the adduct from 8 mols of ethylene oxide with 1 mol of parwtertiary octylphenol 1 mol of para-tertiary octylphenol 4 parts of oleic acid, pure (12) 7 0.3 part of the brightener of the Formula 1 2 parts of dioxane 10 parts of polyethyleneglycol of molecular weight 300 5 parts of the adduct from 8 mols of ethylene oxide with e 1 mol of para-tertiary octylphenol 4.5 parts of oleic acid, pure.

0.075 part of the brightener of the formula 10 parts of dioxane E 1 3 4 parts of the adduct from 8 mols of ethylene oxide with Xaml? e 1 mol f para tertiary octylphenol The under-mentioned solutions (a) to (e) are prepared 4 parts of oleic acid Pure by first dissolving the brightener at room temperature in (8) the relevant solvent, then adding the adduct from ethylene 4O oxide with alkylphenol, shaking the mixture well and 0075 P of bflghtenef 0f the formula finally adding the fatty acid or its sodium salt. (7) (EH; The further procedure is as described in Example 1.

N O O 0.075 part of the brightener of the Formula 1 10 parts of dimethylformamide 4 parts of the adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol 4 parts of oleic acid, pure A 0.075 part of the brightener of the Formula 1 10 parts of dioxane 10 parts of propanol l 4 i ii from g f ethylene oxide with 4 parts of the adduct from 8 mols of ethylene oxide with 4 fe Camry y P am 1 mol of para-tertiary octylphenol Par 5 o o em pure 4 parts of oleic acid, pure (9) 0.075 a tof the br' ht ner of th F0 mul 1 10 s e e r a 0.075 part of the brightener of the formula 3 parts of oleic acid polyglycol ester from polyglycol of N N HCCH molecular weight 300 H H CHEM 3 parts of polyethyleneglycol tertiary dodecyl thio ether 1.2 parts of oleic acid, pure 0.8 part of water 10 parts of fi-hydroxyethyl-n-butyl ether Most of the dioxane 1S dlsmled Off under vacuum 4 parts of the adduct from 8 mols of ethylene oxide with (10) 1 mol of para-tertiary octylphenol 0.075 part of the brightener of the formula 4 Parts of 0161c Pure (8) N N 0.075 part of the brightener of the Formula 1 10 parts of dioxane i I 8 parts of the adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol 0.2 part of lauric acid 0.075 part of the brightener of the Formula 1 10 parts of dioxane 8 parts of the adduct from 8 :mols of ethylene oxide with 1 mol of para-tertiary octylphenol 0.2 part of sodium stearate The viscose, admixed with the brightening agent, can either be spun into long fibers or shaped into foils.

Example 4 0.075 part of the brightener of the Formula 1 or 9/ is dissolved in 10 parts of tetrahydrofuran at room temperature. This solution is mixed with 4 parts of an adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol, thoroughly agitated, and 4 parts of oleic acid are then added. Finally, the tertahydrofuran used as additional solvent is distilled otf under atmospheric or reduced pressure. The incorporation of the solution in the viscose mass is carriel out as described in Example 1.

Example 5 0.075 part ;of the brightener of the Formula 1 is agitated with 8 parts of a reaction product from 5 mols of ethylene oxide with 1 mol of para-nonylphenol, and the resulting solution is incorporated with the viscose mass as described in Example 1.

Example 6 0.075 part of the brightener of the Formula 9 is thoroughly mixed by being agitated with -8 parts each of the following products:

(a) adduct from 8 mols of ethylene oxide with 1 mol of para-tertiary octylphenol,

(b) adduct from 5 mols of ethylene oxide with 1 mol of para-nonylphenol and (c) condensation product obtained from 1 mol of coconut oil fatty acid and 2 mols of diethanolamine, with elimination of 1 mol of water.

The three solutions are then further processed as described in Example 1.

Example 7 0.075 part of the brightener of the Formula 1 is dissolved in parts of dioxane and mixed with 8 parts of one of the following two products:

(a) adduct from 5 mols of ethylene oxide with 1 mol of para-nonylphenol,

(b) condensation product obtained from 1 mol of coconut oil fatty acid and 2 mols of diethanolamine, with elimination of 1 mol of water.

The solution is added to viscose as described in Example 1 and the viscose spinning mass is used for the preparation of long fibers.

Example 8 The procedure of Example 1 is used, except that the resulting, optically brightened fibers are further subjected for 30 minutes at room temperature to a bleaching operation in a hypochlorite bath containing 2 g. of active chlorine per litre of solution. This after-treatment improves the brightening effect substantially.

I claim:

1. Process for the manufacture of optically brightened shaped articles from regenerated cellulose which process comprises adding to the unshaped viscose mass a solution containing from about 0.01% to 1% weight based on the weight of cellulose, of an organic, sparingly watersoluble optical brightening agent selected from the group consisting of dibenzoxazolyl-thiophenes, 4,4'-ditriazinylaminostilbene 2,2'-disulfonic acids, coumarins and 1,4-distyrylbenzene and a nonionic emulsifying agent selected from the group consisting of addition products of ethylene oxide with higher alcohols, para-alkylphenols and higher alkylmercaptans and of the reaction product of higher fatty acids with hydroxy alkylamines, the weightratio between the optical brightening agent and the emulsified being between 1:20 and 1:500 and submitting the viscose mass to coagulation and shaping.

2. Process according to claim 1, wherein the brightener solution contains an organic solvent for the optical brightening agent which solvent is miscible with water in all proportions.

3. Process according to claim 1, wherein the shaped articles are fibers and foils. I

4. Process for the manufacture of fibers from regen erated cellulose which process comprises adding to the unshaped viscose mass a solution containing from about 0.01% to 1% by weight, based on the weight of cellulose, of the optical brightener having the formula on, N N 111, no-on H3 0 H H c on,

I c-o o-o l ona on which is dissolved in dioxane, pure oleic acid and the condensation product of one mol of p-tertiary-octylphenol with eight mols of ethylene oxide, the weight-ratio between the optical brightener and the condensation product being between 1:20 and 1:500, and submitting the viscose mass to coagulation.

6. Process for the manufacture of fibers from regenerated cellulose which process comprises adding to the unshaped viscose mass of solution containing from about 0.01% to 1% by weight, based on the weight of cellulose, of the optical brightener having the formula which is dissolved in dioxane, pure oleic acid and the condensation product of one mol of p-tertiary-octylphenol with eight mols of ethylene oxide, the weightratio between the optical brightener and the condensation product being between 1:20 and 1:500, subjecting the viscose mass to coagulation to produce fibers and subsequentially to the coagulation subjecting the optically brightened fibers to a chlorine bleaching treatment.

References Cited UNITED STATES PATENTS 6/ 19 63 Duennenberger et al. 260307 6/ 1964 Maeder et a1 260-307 HOSEA E. TAYLOR, I 11., Primary Examiner R. W. GRIFFIN, Assistant Examiner U.S. Cl. X.R.

22g? UNITED STATES PATENT OFFICE 5533/E/CIP CERTIFICATE OF CORRECTION Patent No. 3,508,9U2 Dated April 28, 1970 Inventor(S) Horst NObs It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, claim t, the left-hand side of the structural formula should read Signed and sealed this 3rd day of August 1971 (SEAL) Attest:

EDWARD PLFLETGHERJR. Attesting Officer WILLIAM E. SCHUYLER, JR. Commissioner of Patents 

